Tamoxifen vs AI

LGP1111

Hi there, I so appreciate this discussion board. I've learned so much and have been so comforted by it. I'm "done" with treatment - double mastectomy, dose dense ACT chemo, radiation, and hysterectomy/oopherectomy, and reconstruction. Currently on tamoxifen (95% ER+/80% PR+). I've met with several oncologists - one advises tamoxifen because of bone protection, the other recommends an AI since I'm now post menopausal. I've had a remarkable lack of side effects/symptoms from tamoxifen and ovary removal. Very few hot flashes,no vaginal dryness, etc. Instead of celebrating this, I'm terrified that a) I'm resistant to/can't metabolize tamoxifen and/or b) am still being exposed to estrogen from some dietary or environmental source. Just reaching out to gather opinions. Tamoxifen vs AI....a few years on each? Thanks so much for sharingyour thoughts/personal experience.

Kathleen26

I've been on Tamoxifen for close to 3 years, after 18 months or so on an AI. I too have little noticeable side effects from the Tamoxifen, after suffering joint and insomnia issues on the AI's. Now I'm getting close to 5 years out, so I figure that either the Tamoxifen is working for me, or the cancer wasn't going to come back anyway.

I think there's a test your doctor can have done to test for an inability to metabolize tamoxifen into the active form your body needs. I don't know whether you need a reason to get that test. I suppose it is highly likely that I am still being exposed to estrogens from my diet and from my own body (not from my ovaries, those have been removed). The point of Tamoxifen is to block those from any cancer cells. Lots of doctors want post-menopausal women on the AI's because they are slightly more effective, meaning that a few more women won't get a recurrence than if they were on Tamoxifen. It doesn't mean that Tamoxifen is not effective in post-menopausal women.

I don't think there's anything wrong with giving the AI's a try and see if you are also lucky with those. My sister took an AI for 5 years and claims to have never had a single side effect. The good thing is that most side effects are reversible, so if you decide you want to go back to Tamoxifen, you may gain back some lost bone if that happens on the AIs, and other side effects like joint pain should subside. Changing from one to the other and back again is certainly doable. it's not an irrevocable decision. I would think any doctor would rather have you on something, rather than have a patient on nothing because they can't stand the side effects.

LGP1111

Thank you so much for your thoughts, kathleen26. I appreciate hearing about your experience. Glad you are doing well.

sugarplum

I'm also terrified - at the prospect of switching to Tamoxifen after 8 successful years on Arimidex. Sure I've had joint pain and insomnia, but I always considered them as the tradeoff for being on the most effective medication. Now my spine has finally deteriorated almost to the point of osteoporisis and my onc is wanting me to switch over to Tamox. I'm worried about the new side effect profile, and about a recent study I saw that revealed Tamox is rendered ineffective if your melatonin levels aren't high enough during the night. I've had 6 annual Reclast infusions but it seems they are no longer able to combat the Arimidex damage. I already have a new bottle of Tamox but have put it in a drawer as I just can't face switching right now!

Will be interested to hear other's responses to your post.

All the best, Julie

Kathleen26

I've heard of people taking Tamoxifen also taking melatonin in the evening. I tried it, but it didn't find it to help me sleep, so I gave up on it. Maybe you can look into that. Osteoporosis can be terribly debilitating, so you don't want to risk that if you don't have to.

Even Arimidex doesn't work for everyone, or stops working after working for a while, so it's all a crap shoot at some point. I was also pretty upset when my doctor took me off the AI's (due to liver issues) and suggested Tamoxifen. But I researched it and realized it was my best overall option. So far it's working out. Does it mean the cancer will never come back for sure? Nope, we (here) know better.

Anonymous

LGP: I was on tamoxifen for a little over 5 years with almost no SE's. Now onc has put me on Femara and the only SE's are probably joint pain & some cramping in legs and feet, but that was common on tamoxifen too. Onc says Femara will do a better job at blocking estrogen than Tamoxifen, particularly since I'm post-meno. I opted for Femara over Arimidex because of some I know that had awful reactions to the Arimidex. But the onc said if I couldn't tolerate the Femara we can also go back to Tamoxifen for another 5 years.

Sugarplum - so sorry to hear about the spine issues. How often are you getting a Dexa scan? I haven't had one in more than 2 years.

Shelly

sugarplum

Shelly-I've gotten Dexas every December since I went on Arimidex in 2006. Before that I think all I had was a baseline Dexa, but I was already osteopenic even before diagnosis. That's probably why they've been watching me so closely. I'm flinching at every back twinge these days as I don't know if my spine is getting ready to snap! And yet, every night I put another little Arimidex in my mouth and pray it's still doing its job. My onc will probably put a stop to that when I see him in June.....

Julie